Update flutter_sdk example to include hotspot provisioning widget

[jckras]

(https://viam.atlassian.net/browse/APP-9925) - This PR adds the hotspot provisioning example app to the examples found in the flutter sdk. I took this exact example app from the hotspot provisioning package https://github.com/viamrobotics/viam_flutter_hotspot_provisioning_widget/tree/main/example/hotspot_provisioning and added it to the same directory as the other example apps that live in the flutter sdk.

One thing to note about the dependencies here - there's a circular dependency between these packages. The viam_flutter_hotspot_provisioning_widget package depends on viam_sdk, so if I set viam_sdk to use a local path in this example, it creates a conflict where the example would reference the local viam_sdk while the hotspot provisioning widget references the published version. To avoid version mismatches, I had to set viam_sdk to reference a published version instead of the local path.

Also note: I know this is a large amount of files because I am importing an entire example app. Let me know if there is a better way to go about this. The main changes exist in lib/, README.md and pubspec.yaml.

[jckras]

Video running example app on ios:

ScreenRecording_11-03-2025.09-21-36_1.MP4

[jckras]

@stevebriskin adding you as a reviewer since you requested this. let me know if there's something different you were thinking

[kevin49999]

nit - del extra lines

[njooma]

seems reasonable % kevin's nit (which i agree with)